Moon and Antares

The Moon forms a gentle arc with two bright pinpoints of light tonight. Antares, the brightest star in Scorpius, is to the lower left of the Moon as night falls, with the slightly brighter planet Saturn to the right or upper right of the Moon.

Both Antares and Saturn belong to families of similar objects. Saturn is the second largest of the eight major planets in our own solar system. And Antares is the largest member of a family of stars known as Upper Scorpius — part of a larger complex of stars that spans many light-years.

Upper Scorpius contains hundreds of stars that formed from a single giant cloud of gas and dust about 10 million to 12 million years ago. Despite their similar ages, though, they’re not all in the same phase of life.

For most stars, an age of a few million years is quite young. In fact, most of the stars of Upper Scorpius haven’t even arrived at stellar adulthood. These stars will live hundreds of millions to billions of years.

Antares is the same age as those stars, but it’s already well into its final stages because it’s one of the giants of the galaxy — roughly 17 or 18 times as massive as the Sun. The nuclear furnaces at the cores of such massive stars run at a furious rate, “burning” through their original nuclear fuel in a hurry.

Sometime in the next million years or so, Antares is likely to explode as a supernova — while most of its stellar siblings are just getting started.

Script by Damond Benningfield, Copyright 2014

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